Male and female sex hormones Testosterone production and spermatogenesis Infertility and male hypogonadism Female sex hormones Normal menstrual cycle Human chorionic gonadotrophin(hCG) Effect of pregnancy on biochemical tests Complications in pregnancy

Male sex hormones The male gonads are the testes. Testes have a double function: to produce and secrete the male hormone, testosterone, and to produce the spermatozoa. The pituitary gonadotropin LH stimulates interstitial cells in the testis to produce testosterone and FSH promotes spermatogenesis by the germinal cells. Plasma testosterone levels in normal adult males range from 350-1200ng/dl (3.5-12 μg/d, and 30-90ng/dl in female.

Investigation of infertility and male hypogonadism

Female sex hormones The female gonad, ovary, has a double function; it not only produces and secretes the female sex hormones, but it is the site of production and maturation of the ova. One mature ovum is released approximately once every 4 or 5 weeks. The reproductive system of female is more complicated than in males because of the cyclical events that take place during the menstrual cycle and even greater changes that occurs during pregnancy. 2 different chemical types of steroid hormones are produced and secreted by ovary in non-pregnant females during pregnancy, the same hormones are produced by the ovary, but in different proportions. The placenta also makes the hormones that necessary for maintenance of pregnancy.

The hypothalamic–pituitary–ovarian axis The hypothalamic–pituitary–ovarian axis. Activins, inhibins and progesterone also have a role in regulating the cycle.

The first group of female sex hormone, the estrogen, originate in the ovarian follicle( and also in the placenta during pregnancy). The estrogens participate in the menstrual cycle and are essential for the development and maintenance of the reproductive organs and secondary sex characteristics. The second group comprises progesterone and its metabolites , which are formed in the corpus luteum, the body that develops from ruptured ovarian follicle. Progesterone is secreted after ovulation, stimulates the uterus to undergo changes that prepare it for implantation of the fertilized ovum and suppresses ovulation and secretion of pituitary LH. IF pregnancy occurs, the secretion of progesterone by the corpus luteum and also by the placenta, suppresses menstruation for the duration of the pregnancy.

Changes in plasma concentrations of FSH, LH and the principal gonadal steroids in the normal menstrual cycle

Oestrogens act on several target tissues, including the uterus, vagina and breast; progesterone mainly acts on the uterus, and is essential for the maintenance of early pregnancy. Both oestrogens and progesterone are important in the control of the hypothalamic–pituitary–ovarian axis. Oestradiol may stimulate or inhibit the secretion of gonadotrophins, depending on its concentration in plasma; the stimulating effect of oestradiol can be prevented by high plasma [progesterone]. Inhibins and activins also play a role in regulating ovarian function and they change during the cycle; however, their measurement is not performed as part of routine investigation. Inhibin B originates from developing follicles

Human chorionic gonadotrophin(hCG) The placenta produces several proteins, including hCG and (human) placental lactogen. It also produces large amounts of steroid hormones and is the main source of progesterone during pregnancy. The most commonly measured is hCG. Following synthesis, hCG is secreted into the maternal circulation. There is a surge in maternal [hCG] in early pregnancy, peak blood levels being reached at 12 weeks; there after, production of hCG rapidly declines. hCG becomes detectable in urine about 10 days after conception, and this forms the basis of readily available pregnancy tests.

Changes in TSH, thyroid hormones, hCG and TBG in normal pregnancy Changes in TSH, thyroid hormones, hCG and TBG in normal pregnancy. For TSH and thyroid hormones it is important to use gestational or trimester related reference ranges. In some pregnancies TSH may fall to <0.1 mU/L in the first trimester. Total T3 and FT3 follow the same pattern as total T4 and FT4, respectively.

Effect of pregnancy on biochemical tests Serum prolactin, oestrogens and testosterone show a steady increase in pregnancy . There are large increases in serum cortisol due to increased serum cortisol binding globulin (CBG). In normal pregnancy there is an increase in the pool size of extra-thyroidal T4 and an increase in the deiodination of thyroid hormones from the developing placenta. During pregnancy, the plasma volume and GFR increase, sometimes by as much as 50%. And decreases in, for example, serum[sodium], [urea] and [creatinine].

Serum triglyceride may increase as much as 3-fold in pregnancy; serum cholesterol, LDL and HDL increase to a lesser extent. In pregnancy, the placental isoenzyme of ALP is released, and total ALP activity in serum may rise to as much as 3 times nonpregnant levels. In contrast, the expansion of the extracellular fluid leads to a fall (∼20%) in the activities of the transaminases and in the concentration of bilirubin. During pregnancy, serum [ferritin] and serum [iron], are decreased due to increased maternal red cell synthesis and transfer of iron to the developing fetus.

Complications in pregnancy Ectopic pregnancy. In ectopic pregnancy, serum [hCG] fails to rise at the normal rate (approximately doubling every 2–3 days). Diabetes mellitus. Women with type 1 diabetes are at greater risk from both diabetic and obstetric complications during pregnancy. They need for careful home glucose monitoring (4–6 times a day) and intensive insulin regimens. Women should aim to maintain blood glucose and HbA1c concentrations as near to the nondiabetic range as possible without excessive risk of hypoglycaemia. Type 2 diabetes is less common during the reproductive years, but its management during pregnancy should follow the same intensive pattern.